Democrats have lost seven of the last 10 presidential elections in part because voters deemed them weak on national security. Could it happen again in 2008, when nearly every other issue is cutting in favor of Democrats regaining the White House? Yes, and for good reason.

First, for any who hadn't noticed, America is at war; in Iraq, in Afghanistan, and in a shadowy but lethal struggle around the world with terrorists determined to kill us. Second, the Democrats who control Congress and the Democrats running for president are, with only occasional exceptions, reinforcing the impression that their national security credentials are deeply suspect.

Discerning Democrats will note that it isn't only Republicans who are saying so.

Joe Klein, a politically astute columnist notably hard on George Bush, writes this in the Dec. 3 issue of Time magazine: "If the Democrats want to win in 2008, they can't be mealymouthed on issues of national security." Klein then proceeds to cite two matters, Iraq war funding and surveillance of terrorist communications, about which Democrats have been "foolishly partisan." Klein concludes by warning that if Democrats can't credibly promise to "protect the nation against enemies, foreign and domestic ... they simply will not win the presidency."

Similarly, the Democratic Leadership Council, founded in the 1980s to move the Democratic Party from the left to the center, has been warning for years that a failure to project strength on national security, especially in time of war, invites electoral defeat. Ditto for Sen. Joe Lieberman, Democrat turned independent, and any number of blue dog Democrats.

These voices of political reason, however, are barely heard and rarely heeded these days amid the Democrats' partisan fury on Capitol Hill and Bush-bashing frenzy on the presidential campaign trail. Instead, most Democrats seem far more driven by their party's MoveOn.org wing, which in saner times would be known as the looney left. MoveOn's extremism is defined by, for example, its sponsorship of infamous political ads equating George Bush with Adolf Hitler and Iraq commander Gen. David Petraeus with "General Betray Us."

Leaning left may be smart politics for Democratic presidential aspirants competing for support from their party's disproportionately liberal voters in primary contests. It would likely be fatal in a general election decided by the electorate's sensible center.

It doesn't appear to be playing well for congressional Democrats, either. Public approval ratings for the new Democratic Congress' performance are hovering around 20 percent, a third lower than Bush's anemic standing in the polls and among the lowest congressional ratings ever recorded.

Applying the Joe Klein test of national security fitness begins with funding for U.S. forces fighting in Iraq. By the latest count, the Democratic-controlled Congress has voted 40 times this year on legislation that would force a withdrawal of troops from Iraq, micromanage their deployments for the same purpose or condemn the surge in American troop strength in Iraq. All to no avail.

Democrats lack the votes to overcome either a Republican filibuster in the Senate or Bush's certain veto of any legislation rewriting the Constitution to make Congress, not the president, commander in chief of America's armed forces.

In their frustration, Democrats are now doing what they earlier vowed not to - refusing additional funding for American troops fighting on a foreign battlefield. What most Democrats concluded last spring would be politically suicidal is now the congressional weapon of choice to compel an American retreat, and defeat, in Iraq.

This budgetary game of chicken, with the safety and combat effectiveness of American soldiers and Marines hanging in the balance, is the handiwork of House Speaker Nancy Pelosi and Senate Majority Leader Harry Reid. But the Democrats' leading presidential contenders, Hillary Clinton and Barack Obama, are complicit. Both voted in November against the Bush administration's request for $70 billion in emergency Iraq funding.

Last April, Obama said, "nobody wants to play chicken with our troops on the ground ... you don't want to play chicken with the president and create a situation in which, potentially, you don't have body armor, you don't have reinforced Humvees, you don't have night-vision goggles." During that same April debate, Sen. Clinton said "of course" she would eventually support legislation funding the troops.

Shades of John Kerry's "I actually voted for it before I voted against it," the revealing gaffe that helped doom his presidential campaign.

What makes this Draconian gambit by Democrats especially damaging to their political fortunes is its paradoxical timing. Just as the troop surge is, by every account, achieving remarkable military gains in Iraq, Democrats in Congress and on the presidential campaign trail continue to insist that we've lost and should retreat. The latest polls (Rasmussen and Pew) show that nearly half of all Americans, up from only a third earlier this year, now believes that the Iraq war is going very well or fairly well. Yet, the Democrats appear oblivious to the changing facts on the ground.

Hillary Clinton, the least dovish of all the Democratic presidential candidates, greeted Gen. Petraeus' cautious optimist last September by saying that believing him required "the willing suspension of disbelief." No word on what she thinks now.

Democratic Rep. John Murtha, the gruff ex-Marine who became the unlikely hero of anti-war Democrats by calling long ago for withdrawal from Iraq, just returned from a Thanksgiving visit there saying, "I think the 'surge' is working." But then, Murtha isn't running for president.

On terrorist surveillance, the Democrats had to be dragged kicking and screaming into reforming the antiquated Foreign Intelligence Surveillance Act. The National Security Agency is back in business monitoring al-Qaeda's communications, including any with persons inside the United States. Bipartisan compromise accomplished this while protecting Americans' civil liberties, but no thanks to scores of congressional Democrats who still voted no.

Nancy Pelosi insisted on pushing a purely Democratic version that, in effect, gave terrorists the same constitutional protections as American citizens. In the Senate, Hillary Clinton backed a threatened Democratic filibuster of FISA reform despite a pending bipartisan compromise in the Senate Intelligence Committee.

The debate over terrorist surveillance is politically revealing because intelligence gathering is absolutely indispensable to preventing the next 9/11, or worse. Democrats ignore this at their peril.

In 2008, the Democrats' presidential nominee can expect to see all this played back to them in Republican campaign ads charging weakness on national security. Thus might Hillary Clinton or Barack Obama yet lose to a GOP underdog with one ace - undoubted credentials and commitment on national security.

Robert J. Caldwell is editor of The San Diego Union-Tribune's Sunday Insight section and can be reached by e-mail.